1. Field of the Invention
The invention relates to creams and lotions suitable for application to the human skin, and, more particularly, to such creams and lotions containing, at least in part, oil derived from the emu bird.
2. Description of the Related Art
An emu is a large, flightless Australian bird, Dromiceius novaehollandiae, which is related to and resembles the ostrich. The emu is a member of the Ratite family of birds. The emu is the only bird of the Ratite family that has a subcutaneous layer of fat found just under the skin on the back of the bird. Other birds in that family have particular areas of body fat, but not a significant subcutaneous fat layer along the back as in the emu.
Within the last several years, it has become popular to raise and breed emus for commercial purposes. Emus can be commercially valuable livestock in several respects. For example, the meat of the emu may be eaten. That meat is a red meat, like beef from cattle. Emu meat is low in calories, low in cholesterol, high in protein, and high in iron. Further, the skin of the emu can be used as leather. The leather is a high quality, durable leather. It is thin like pigskin and so may be used in much the same manners as pigskin, such as for garments like women's clothing, skirts, jackets, vests, wallets, and boots, and for a multitude of other matters which may be made from leather. Even further, the feathers of the emu may be used in a number of ways. Emu feathers have been used for making fishing lures and in ornamental-type items, for example, jewelry.
Only recently has it become apparent that oil from the emu may have commercial value. Emu oil, in one form or another, has been used for many years by the Aborigines of Australia. The Aborigines have, in particular, used the oil to protect human skin from the adverse elements encountered in the Australian outback. The Aboriginal people have also used emu oil and fat for the treatment of arthritis and rheumatism. In certain of these applications, the Aborigines mix the emu oil with various other oils, for example, cineole or eucalyptus oil. Early explorers and bushmen have also extolled the merits of emu oil as an embrocation for relief of a number of ailments, including rheumatism, lumbago and joint stiffness.
Only recently has white settlement recognized and researched the therapeutic effects of emu oil. Combinations of emu oil and a suitable transdermal transporter have, in various tests, been demonstrated to exhibit anti-inflammatory activity, in the cases of inflammatory arthritis and similar joint swelling diseases. Ghosh, P. and Whitehouse, M., Experimental Study to Determine the Anti-Arthritic Activity of a New Emu Oil Formulation (EMMP), Ostrich Marketplace (Dec. 3, 1992). In those tests, it was found that emu oil exhibits certain surface penetrating characteristics that, when the oil is combined with other compounds, increases the penetration of the composition as a whole. There was indication in those studies that the compositions created some skin irritation. The use of emu oil has, thus, heretofore been considered effective only in combination with anti-inflammatory type compounds in which skin irritation is of less concern than penetrability.
Animal oils in general have not been used in traditional cosmetic formulations because those oils tend to be comedonic or otherwise irritable to the human skin. It has been known, however, that animal oils, due to their particular phospholipid concentrations, which are similar to that of the human skin, have penetration qualities. Nevertheless, though animal oils could have some beneficial penetration characteristics, animal oils have not generally been used in cosmetic creams and lotions because of the undesirable skin irritation consequences.
Various compounds in creams and lotions are presently recognized as medically active and beneficial when applied to the human skin. Certain of these compounds which have received considerable attention as of late include alpha-hydroxy acids. Alpha-hydroxy acids are commonly known as "fruit acids," because most are derived from apples, citrus, and grapes. The family of alpha-hydroxy acids includes a number of compounds, including, for example, lactic acid and glycolic acid. Alpha-hydroxy acids have certain desirable moisturizing characteristics and so have been used in various cosmetic compositions. Alpha-hydroxy acids act as moisturizers by loosening dead skin cells from the skin surface. They have much the same effect as a rough cloth or sponge that rubs off surface skin cells to uncover fresher cells. In technical terms, these acids reduce the thickness of hyperkeratotic stratum corneum by reducing corneocyte cohesion at lower levels of the skin stratum corneum. This property permits efficient clinical control of dry skin, ichthyosis, follicular hyper-keratosis, and other conditions characterized by retention of stratum corneum. Van Scott, E. J., and Yu, R. J., Alpha-Hydroxy Acids: Procedures for Use in Clinical Practice, Cutis (March 1989).
In addition to the alpha-hydroxy acids, a multitude of other substances, because of their desirable moisturizing characteristics, are used in cosmetic compositions. A substance being used only fairly recently in cosmetics is liposomes. Liposomes are microscopic bubbles formed of a lipid shell which encapsulate a portion of the solution in which the liposome is found. Liposomes may be manufactured and filled with a variety of medications. The capsule shell of liposomes may be similar in composition to the body's own skin oil. Therefore, liposomes can serve to penetrate into the deep underlying layers of the skin where they then deliver their active moisturizing agents in a time-release action. Topical use of liposome drugs have been described in the literature. Korting, H.C., Blecher, P., Schafer-Korting, M., and Wendel, A., Topical Liposomes to Come, What the Patent Literature Tells Us, Journal of the American Academy of Dermatology (December 1991). Though liposomes have been observed to be somewhat effective when used in topical cosmetic applications due to their skin penetrating characteristics, the major focus for use of liposomes in the past has been with topical inflammatory agents, in particular, corticosteroids.
Even liposomes have proven only partially effective in providing adequate penetrability, as desired for many cosmetics applications. Further, the addition of liposomes to cosmetics preparations can significantly increase the cost of the preparations. Clearly, it would be both technologically and commercially advantageous to use some other or additional penetrating composition in cosmetics to achieve desired penetration results. The present invention provides a significantly improved cosmetic compound, effective in providing desired penetration in human skin and, yet, maintaining appropriate effectiveness of the compound as a whole, without adverse consequences to the user or otherwise. Further, the present invention is more cost-effective than many of the penetrating compounds heretofore employed. The present invention is thus a significant improvement in the art.